Very interesting.... The forums did relocate to a new host recently to expand our capacity. Looks like there might be some quirks with the setup.

Everyone, please remain calm, I'll see if either me or Ryan can get in contact with a server admin to figure out what is causing these alerts.

As far as a DRDOS, I can assure you nobody at Canonical or the forums is trying to cause a DRDOS attack on you... It's most likely a false positive resulting from some sort of screwed up packet.